[Mojo Video Capture] Stop service when last client disconnects.

services/video_capture/public/interfaces/service.mojom

Index: services/video_capture/public/interfaces/service.mojom
diff --git a/services/video_capture/public/interfaces/service.mojom b/services/video_capture/public/interfaces/service.mojom
index a08ae596bb4164dc28188c68364c1271df594e8f..70a81185f173407d5e30cb195fa79bfecc371ff7 100644
--- a/services/video_capture/public/interfaces/service.mojom
+++ b/services/video_capture/public/interfaces/service.mojom
@@ -17,4 +17,11 @@ import "services/video_capture/public/interfaces/device_factory.mojom";
 interface Service {
   ConnectToDeviceFactory(DeviceFactory& request);
   ConnectToFakeDeviceFactory(DeviceFactory& request);
+
+  // The service shuts down after a certain delay when no client is connected.
+  // This method allows clients to customize this delay.
+  // An example use case for a custom delay is integration tests that want to
+  // minimize wait time.
+  // The default value is found in constants.mojom.
+  SetShutdownDelayInSeconds(float seconds);
 };